In the present work the frequency of micronuclei (MN) in exfoliated buccal cells in 120 healthy individuals with relation to sex, age and smoking was investigated. Neither age nor sex showed any effect on the level of micronuclei. Smoking has shown a significant effect upon basal DNA damage. In the present study the calculated background frequency of micronuclei (parts per thousand) in oral epithelial cells of 50 smokers and 70 non-smokers were 1.50 (+/-0.47) and 0.55 (+/-0.32), respectively.